Activating Nrf-2 signaling depresses unilateral ureteral obstruction-evoked mitochondrial stress-related autophagy, apoptosis and pyroptosis in kidney

PLoS One. 2012;7(10):e47299. doi: 10.1371/journal.pone.0047299. Epub 2012 Oct 10.

Abstract

Exacerbated oxidative stress and inflammation may induce three types of programmed cell death, autophagy, apoptosis and pyroptosis in unilateral ureteral obstruction (UUO) kidney. Sulforaphane activating NF-E2-related nuclear factor erythroid-2 (Nrf-2) signaling may ameliorate UUO-induced renal damage. UUO was induced in the left kidney of female Wistar rats. The level of renal blood flow, cortical and medullary oxygen tension and reactive oxygen species (ROS) was evaluated. Fibrosis, ED-1 (macrophage/monocyte) infiltration, oxidative stress, autophagy, apoptosis and pyroptosis were evaluated by immunohistochemistry and Western blot in UUO kidneys. Effects of sulforaphane, an Nrf-2 activator, on Nrf-2- and mitochondrial stress-related proteins and renal injury were examined. UUO decreased renal blood flow and oxygen tension and increased renal ROS, 3-nitrotyrosine stain, ED-1 infiltration and fibrosis. Enhanced renal tubular Beclin-1 expression started at 4 h UUO and further enhanced at 3d UUO, whereas increased Atg-5-Atg12 and LC3-II expression were found at 3d UUO. Increased renal Bax/Bcl-2 ratio, caspase 3 and PARP fragments, apoptosis formation associated with increased caspase 1 and IL-1β expression for pyroptosis formation were started from 3d UUO. UUO reduced nuclear Nrf-2 translocation, increased cytosolic and inhibitory Nrf-2 expression, increased cytosolic Bax translocation to mitochondrial and enhanced mitochondrial Cytochrome c release into cytosol of the UUO kidneys. Sulforaphane significantly increased nuclear Nrf-2 translocation and decreased mitochondrial Bax translocation and Cytochrome c release into cytosol resulting in decreased renal injury. In conclusion, sulforaphane via activating Nrf-2 signaling preserved mitochondrial function and suppressed UUO-induced renal oxidative stress, inflammation, fibrosis, autophagy, apoptosis and pyroptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis*
  • Autophagy*
  • Cytochromes c / metabolism
  • Cytosol / metabolism
  • Female
  • Fibrosis
  • Kidney / pathology*
  • Mitochondria / metabolism
  • Mitochondria / physiology
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / metabolism*
  • Rats
  • Rats, Wistar
  • Reactive Oxygen Species / metabolism
  • Regional Blood Flow
  • Signal Transduction
  • Stress, Physiological
  • Ureteral Obstruction / metabolism*
  • Ureteral Obstruction / pathology
  • bcl-2-Associated X Protein / metabolism

Substances

  • Bax protein, rat
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, rat
  • Reactive Oxygen Species
  • bcl-2-Associated X Protein
  • Cytochromes c

Grant support

This work was supported in part by the National Science Council of the Republic of China (NSC 94-3114-P002-002, and NSC94-3114-P002-002-Y(8)) and research funding from the Far-East Memorial Hospital. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.